assert it

Author: dwijnand

compiler/src/dotty/tools/dotc/core/Symbols.scala

@@ -333,7 +333,9 @@ object Symbols extends SymUtils {
       else if (denot.is(ModuleVal))
         this.moduleClass.sourceSymbol // The module val always has a zero-extent position
       else if denot.is(ExportedType) then
-        denot.info.dropAlias.asInstanceOf[NamedType].symbol.sourceSymbol
+        val tp = denot.info.dropAlias
+        assert(tp.isInstanceOf[NamedType], i"denot=$denot info=${denot.info} tp=$tp ${tp.toString}")
+        tp.asInstanceOf[NamedType].symbol.sourceSymbol
       else if (denot.is(Synthetic)) {
         val linked = denot.linkedClass
         if (linked.exists && !linked.is(Synthetic))